A teleconferencing system comprises a conference bridge having a multichannel connection to each customer equipment. The customer equipment has a unit to separately process each channel to provide one output representing each of the other participants. These outputs can be combined in a spatializer to provide a spatialized output in which each participant is represented by a virtual sound source. The conference bridge comprises a concentrator, having a unit to identify the currently active input channels and to transmit only those active channels over the multichannel connection, together with control information identifying the transmitted channels.